In cancer, normal epigenetic silencing and cytosine methylation are disrupted. Dietary intake of methyl donors can directly affect epigenetic mechanisms through cytosine methylation. Our longterm goal is to understand how the risk of human disease, cancer in particular, is affected by epigenetics and diet. We use A10-vy (obese yellow) mice, a model that exhibits a highly variable phenotype of obesity, tumors, and type II diabetes; the expression of the syndrome is under epigenetic control. The epigenetic state of the A-vy allele can be inherited, indicating that the epigenetic marks determining the behavior of the allele are maintained in the germline. Supplementation of the maternal A-vy diet with methyl donors during gestation alters phenotypes in offspring. We hypothesize that continuous supplementation of the maternal diet with methyl donors will produce a cumulative increase in methylation of the A-vy allele, resulting in a multigenerational trend toward suppression of the obese yellow phenotype, and denser methylation of the allele. The changes may persist after supplementation is withdrawn. Our specific aims are: 1. Investigate the effects of continuous methyl donor supplementation on inheritance of the obese yellow phenotype in A-vy mice. Continuous feeding of methyl donors to A-vy mothers may produce changes in phenotype that increase with more generations. 2. Ask if the effects of methyl donor supplementation persist for generations when supplementation is withdrawn. Changes induced by methyl donors may be maintained in the germline, resulting in epigenetic "memory" that persists for one or more generations. 3. Investigate effects of methyl donor supplementation on CpG methylation of the A-vy allele We will use bisulphite allelic sequencing to obtain a detailed picture of the methylation status of the allele in mice bred for Aims 1 and 2.